find -not -name not working

If you want code rather than a suggestion for fixing the issue, which is that the unexpected filename in question may have trailing space or other non-printing characters embedded in it, here you go. This implements what I understand from your question, which is to delete files and directories that are older than a day:

#!/bin/bash

base='/volume1/Ingest'
days=1

# Find directories not modified for a day
readarray -d '' -t dirs < <(find "$base" -depth -type d -mtime +"${days:-1}" -print0)

# Check files in each directory
for dir in "${dirs[@]}"
do
    printf 'DIRECTORY %s\n' "$dir"
    find -- "$dir" -maxdepth 1 ! -type d ! -name '*.txt' -mtime +1 -printf 'DELETE %P\n' ## -delete

    if [ "$(find -- "$dir" -maxdepth 1 -printf '.' 2>/dev/null | wc -c)" -gt 1 ]
    then
        printf 'DELETE DIRECTORY %s\n' "$dir"
        ## rmdir -- "$dir"
    fi

    echo
done

This code will avoid *.txt files in every directory, per your question. You can remove or comment the printf statements in the Check files… loop if you want the process to be silent. Uncomment the two ## elements to delete your files and directories; otherwise it's just a reporting tool

Thanks for every bodies help. I ended up taking a different direction and thought I would share the code.

#!/bin/bash

DIR="/volume1/Ingest"
DAYS=1
KEEP="*.txt"

echo
echo "Refreshing modification time of top-level *.txt files"
find "$DIR" -maxdepth 1 -type f -name "$KEEP" -exec touch {} \;

for f in "$DIR"/$KEEP; do # list date owner and base filename
  [ -f "$f" ] && echo "$(date -r "$f" '+%d-%m-%y %H:%M') $(stat -c '%U' "$f") $(basename "$f")"
done

echo
echo "Deleting directories older than $DAYS day(s)"
find "$DIR" \( \
  -path "$DIR/#recycle" -o -path "$DIR/@eaDir" \
\) -prune -o -type d -mtime +$DAYS -exec rm -r -v {} +

echo
echo "Deleting files older than $DAYS day(s)"
find "$DIR" \( \
  -path "$DIR/#recycle" -o -path "$DIR/@eaDir" \
\) -prune -o -type f -mtime +$DAYS -exec rm -v {} +

Its to delete old files on a Synology NAS but keep *.txt files at top level.